Researchers say having a gene that predisposes you to
conditions like ADHD and addiction may also keep you fit and healthy into
extreme old age.

The DRD4 Gene

The DRD4 gene plays a role in regulating the body’s response
to dopamine (a natural pleasure producing chemical).

People with the DRD4 7R allele do not respond as strongly to
dopamine, and as a result, experience less pleasure from everyday stimuli
(enjoying palatable foods, for example).

People with this genotype have also been shown to have an
increased risk of ADHD and addiction. The increased addiction risk likely
occurs as people seek out more intense dopamine-releasing experiences as a way
to compensate for their under-performing dopamine systems.

However, people with this genotype are also more prone to
greater activity as they seek out pleasure and arousal, and over the long term,
especially once you pass the risky adolescent and young adulthood period, this seems
to encourage longevity.

So a genotype which increases your risk of problems in early
life may decrease your risk of problems in older age by keeping you more active
and healthy.

The Experiment

Researchers collected genotype information from more than
1000, 90 to 109 year old study subjects.

They found that:

The oldest study subjects were most likely to have the DRD4
7R allele.

Compared to people who died at a younger age, people who
lived past 90 were 66% more likely to have the DRD4 7R allele

To further test the link between the DRDR gene and
longevity, the researchers eliminated the gene from a group of mice.

The mice missing the DRD4 gene didn’t live as long (7% to 9.7% fewer days) as the mice with this gene
expression.